ayo/lion

Thijs Louisse 6b1698f90f chore: updated dep versions and made compatible

2020-05-29 17:01:15 +02:00

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Overlay System

import { html } from 'lit-html';
import {
  OverlayMixin,
  withBottomSheetConfig,
  withDropdownConfig,
  withModalDialogConfig,
} from '../index.js';

import '../docs/demo-overlay-system.js';
import '../docs/applyDemoOverlayStyles.js';
import { ref as r } from '../docs/directives/ref.js';

export default {
  title: 'Overlays/System/Overview',
};

The overlay system allows to create different types of overlays like dialogs, toasts, tooltips, dropdown, etc. It's designed to be highly flexible, while still delivering sensible defaults. On top of this, the system was built having accessibility in mind.

For a detailed rationale, please consult Rationale.

export const main = () => html`
  <demo-overlay-system>
    <button slot="invoker">Click me to open the overlay!</button>
    <div slot="content" class="demo-overlay">
      Hello! You can close this notification here:
      <button @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}>
        ⨯
      </button>
    </div>
  </demo-overlay-system>
`;

OverlayController

OverlayController is the single class we instantiate whenever creating an overlay instance. Based on provided config, it will handle:

DOM position (local vs global)
positioning logic
accessibility
interaction patterns

and has the following public functions:

show(), to show the overlay
hide(), to hide the overlay
toggle(), to toggle between show and hide

All overlays contain an invokerNode and a contentNode

contentNode, the toggleable content of the overlay
invokerNode, the element toggles the visibility of the content. For local overlays, this is the relative element the content is positioned to

For DOM position, local refers to overlays where the content is positioned next to the invokers they are related to, DOM-wise. Global refers to overlays where the content is positioned in a global root node at the bottom of <body>.

Configuration

Overlays can be configured in many ways to suit your needs. We go in-depth into each option in the Overlay System - Configuration chapter.

We also export a few preset configuration objects, which you can find here.

withModalDialogConfig
withDropdownConfig
withBottomSheetConfig

You import these using ES Modules, and then simply call them inside your OverlayController instantiation:

const ctrl = new OverlayController({
  ...withModalDialogConfig(),
  invokerNode,
  contentNode,
});

or in your Web Component with OverlayMixin, make sure you override these methods to:

Define configuration
Handle setting up event listeners of toggling the opened state of your overlay
Handle the tearing down of those event listeners
Define a template which includes:
- invoker slot for your user to provide the invoker node (the element that invokes the overlay content)
- content slot for your user to provide the content that shows when the overlay is opened
- _overlay-shadow-outlet, this slot is currently necessary under the hood for acting as a wrapper element for placement purposes, but is not something your end user should be concerned with, unless they are extending your component.

_defineOverlayConfig() {
  return {
    ...withModalDialogConfig
  };
}

_setupOpenCloseListeners() {
  super._setupOpenCloseListeners();
  this.__toggle = () => {
    this.opened = !this.opened;
  };

  if (this._overlayInvokerNode) {
    this._overlayInvokerNode.addEventListener('click', this.__toggle);
  }
}

_teardownOpenCloseListeners() {
  super._teardownOpenCloseListeners();

  if (this._overlayInvokerNode) {
    this._overlayInvokerNode.removeEventListener('click', this.__toggle);
  }
}

render() {
  return html`
    <slot name="invoker"></slot>
    <slot name="_overlay-shadow-outlet"></slot>
    <div id="overlay-content-node-wrapper">
      <slot name="content"></slot>
    </div>
  `;
}

or declaratively in your template with the .config property

<demo-overlay-system .config=${{ ...withModalDialogConfig() }}>
  <button slot="invoker">Click me to open the overlay!</button>
  <div slot="content" class="demo-overlay">
    Hello! You can close this notification here:
    <button
      @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
    >
      ⨯
    </button>
  </div>
</demo-overlay-system>

Responsive switching

Currently we support switching between overlay configurations. Keep in mind however that we do not yet support switching between overlay configurations while the content is shown. If you try, it will close the content if it is open, and the user will need to re-open. Will be supported in the near future.

This can be done declaratively as shown below. Drag the viewport under 600px and open the overlay to see the withBottomSheetConfig applied.

export const responsiveSwitching = () => html`
  <demo-overlay-system
    .config=${{ ...withBottomSheetConfig() }}
    @before-opened=${e => {
      if (window.innerWidth >= 600) {
        e.target.config = { ...withModalDialogConfig() };
      } else {
        e.target.config = { ...withBottomSheetConfig() };
      }
    }}
  >
    <button slot="invoker">Click me to open the overlay!</button>
    <div slot="content" class="demo-overlay">
      Hello! You can close this notification here:
      <button @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}>
        ⨯
      </button>
    </div>
  </demo-overlay-system>
`;

Alternative ways to do it is by setting the event listener manually on the OverlayController instance.

myOverlayCtrl.addEventListener('before-show', () => {
  if (window.innerWidth >= 600) {
    ctrl.updateConfig(withModalDialogConfig());
  } else {
    ctrl.updateConfig(withBottomSheetConfig());
  }
});

Or inside of a Web Component that uses the OverlayMixin, by overriding protected method _defineOverlay, where we can access the OverlayController instance and use the updateConfig method on the controller:

_defineOverlay({ invokerNode, contentNode }) {

  // initial
  const ctrl = new OverlayController({
    ...withBottomSheetConfig(),
    hidesOnOutsideClick: true,
    invokerNode,
    contentNode,
  });

  // responsive
  ctrl.addEventListener('before-show', () => {
    if (window.innerWidth >= 600) {
      ctrl.updateConfig(withModalDialogConfig());
    } else {
      ctrl.updateConfig(withBottomSheetConfig());
    }
  });

  return ctrl;

Below is another demo where you can toggle between configurations using buttons.

export const responsiveSwitching2 = () => html`
  <style>
    .buttons button:not(:first-child) {
      margin: 10px;
    }
  </style>
  Change config to:
  <div class="buttons">
    <button
      @click=${() => {
        document.getElementById('respSwitchOverlay').config = { ...withModalDialogConfig() };
      }}
    >
      Modal Dialog
    </button>
    <button
      @click=${() => {
        document.getElementById('respSwitchOverlay').config = { ...withBottomSheetConfig() };
      }}
    >
      Bottom Sheet
    </button>
    <button
      @click=${() => {
        document.getElementById('respSwitchOverlay').config = { ...withDropdownConfig() };
      }}
    >
      Dropdown
    </button>
  </div>
  <demo-overlay-system id="respSwitchOverlay" .config=${{ ...withBottomSheetConfig() }}>
    <button slot="invoker">Click me to open the overlay!</button>
    <div slot="content" class="demo-overlay">
      Hello! You can close this notification here:
      <button @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}>
        ⨯
      </button>
    </div>
  </demo-overlay-system>
`;

Opened state

For any overlay that implements the OverlayMixin, there is a Boolean property opened that reflects whether the overlay content is displayed or not.

You can also listen to the event opened-changed which is fired whenever opened is toggled. This can be useful e.g. if somewhere in your application you need to rely on this "state".

export const openedState = () => {
  const appState = {
    opened: false,
  };
  const refs = {};
  function onOpenClosed(ev) {
    appState.opened = ev.target.opened;
    refs.openedState.innerText = appState.opened;
  }
  return html`
    appState.opened: <span #openedState=${r(refs)}>${appState.opened}</span>
    <demo-overlay-system .opened="${appState.opened}" @opened-changed=${onOpenClosed}>
      <button slot="invoker">Overlay</button>
      <div slot="content" class="demo-overlay">
        Hello! You can close this notification here:
        <button
          @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
        >
          ⨯
        </button>
      </div>
    </demo-overlay-system>
  `;
};

Intercepting open/close

It is possible to intercept the open/close process by calling .preventDefault() on the before-close or before-open events.

export const interceptingOpenClose = () => {
  // Application code
  let blockOverlay = true;
  const refs = {};
  function intercept(ev) {
    if (blockOverlay) {
      ev.preventDefault();
    }
  }
  return html`
    Overlay blocked state:
    <button
      #statusButton=${r(refs)}
      @click="${() => {
        blockOverlay = !blockOverlay;
        refs.statusButton.textContent = blockOverlay;
      }}"
    >
      ${blockOverlay}
    </button>
    <demo-overlay-system
      #overlay=${r(refs)}
      @before-closed=${intercept}
      @before-opened=${intercept}
    >
      <button
        slot="invoker"
        @click=${() => console.log('blockOverlay', blockOverlay, 'opened', refs.overlay.opened)}
      >
        Overlay
      </button>
      <div slot="content" class="demo-overlay">
        Hello! You can close this notification here:
        <button @click=${() => (refs.overlay.opened = false)}>⨯</button>
      </div>
    </demo-overlay-system>
  `;
};

OverlayMixin

OverlayMixin is a mixin anyone can use to create a Web Component which has a content node (slot="content") and invoker node (slot="invoker").

Under the hood, the OverlayMixin will instantiate an OverlayController with these nodes.

By default, there are only a few OverlayMixin methods you need to override to create a working Web Component using an overlay:

render, the template needs to include a <slot name="content">, <slot name="invoker"> and <slot name="_overlay-shadow-outlet">.
_defineOverlayConfig, in this protected method, return an object that contains the default configuration for your Web Component's overlay. See configuration section of OverlayController.
_setupOpenCloseListeners, use this lifecycle hook to setup the open and close event listeners on your _overlayInvokerNode.
_teardownOpenCloseListeners, use this lifecycle hook to ensure that the listeners are removed when the OverlayController is tearing down. For example when the Web Component is disconnected from the DOM.

import { LitElement } from '@lion/core';
import { OverlayMixin } from '@lion/overlays';

class MyOverlayWC extends OverlayMixin(LitElement) {
  _defineOverlayConfig() {
    return {
      placementMode: 'global',
      hasBackdrop: true,
    };
  }

  _setupOpenCloseListeners() {
    super._setupOpenCloseListeners();
    this.__toggle = () => {
      // opened is the public boolean property to use in the WC for opening/closing
      this.opened = !this.opened;
    };

    // Always guard this, because your user may toggle the opened state through something else (e.g. event) and not an invoker node.
    if (this._overlayInvokerNode) {
      this._overlayInvokerNode.addEventListener('click', this.__toggle);
    }
  }

  _teardownOpenCloseListeners() {
    super._teardownOpenCloseListeners();

    if (this._overlayInvokerNode) {
      this._overlayInvokerNode.removeEventListener('click', this.__toggle);
    }
  }

  render() {
    return html`
      <slot name="invoker"></slot>
      <slot name="_overlay-shadow-outlet"></slot>
      <div id="overlay-content-node-wrapper">
        <slot name="content"></slot>
      </div>
    `;
  }
}

OverlaysManager

The OverlaysManager is a global registry keeping track of all different types of overlays. The need for a global housekeeping mainly arises when multiple overlays are opened simultaneously.

For example, you may have a modal dialog that open another modal dialog. The second dialog needs to block the first. When the second dialog is closed, the first one is available again.

The overlay manager keeps track of all registered overlays and controls which one to show.

Below an example is shown with the isBlocking option, which makes use of the OverlaysManager's capabilities.

export const overlayManager = () => html`
  <demo-overlay-system .config=${{ hasBackdrop: true }}>
    <button slot="invoker">Click me to open the overlay!</button>
    <div slot="content" class="demo-overlay">
      Hello! You can close this notification here:
      <button @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}>
        ⨯
      </button>
      <div>
        <button @click=${() => (document.getElementById('secondOverlay').opened = true)}>
          Click me to open another overlay which is blocking
        </button>
      </div>
    </div>
  </demo-overlay-system>
  <demo-overlay-system id="secondOverlay" .config=${{ hasBackdrop: true, isBlocking: true }}>
    <div slot="content" class="demo-overlay demo-overlay--second">
      Hello! You can close this notification here:
      <button @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}>
        ⨯
      </button>
    </div>
  </demo-overlay-system>
`;

Local Backdrop

We provide a possibility to add a backdrop to a locally placed overlay. You can pass your backdropNode as a configuration parameter and control its styling reacting upon OverlayController events. Here is the example below

export const localBackdrop = () => {
  let backdropNode = document.createElement('div');
  backdropNode.classList.add('local-backdrop-01');
  return html`
    <style>
      .local-backdrop-01 {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        z-index: 1;
        background-color: red;
        opacity: 0.3;
        display: none;
      }
    </style>
    <demo-overlay-system
      @before-opened=${e => (backdropNode.style.display = 'block')}
      @before-closed=${e => (backdropNode.style.display = 'none')}
      .config=${{ hasBackdrop: true, placementMode: 'local', backdropNode }}
    >
      <button slot="invoker">Click me to open the overlay!</button>
      <div slot="content" class="demo-overlay">
        Hello! You can close this notification here:
        <button
          @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
        >
          ⨯
        </button>
      </div>
    </demo-overlay-system>
  `;
};

Declarative Local Backdrop

Another way to add custom backdrop is declaratively add an element with slot="backdrop".

export const declarativeLocalBackdrop = () => {
  const beforeOpened = () => {
    document.querySelector('.local-backdrop-02').style.display = 'block';
  };
  const beforeClosed = () => {
    document.querySelector('.local-backdrop-02').style.display = 'none';
  };
  return html`
    <style>
      .local-backdrop-02 {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        z-index: 1;
        background-color: red;
        opacity: 0.3;
        display: none;
      }
    </style>
    <demo-overlay-system
      @before-opened=${beforeOpened}
      @before-closed=${beforeClosed}
      .config=${{ hasBackdrop: true, placementMode: 'local' }}
    >
      <div slot="backdrop" class="local-backdrop-02"></div>
      <button slot="invoker">Click me to open the overlay!</button>
      <div slot="content" class="demo-overlay">
        Hello! You can close this notification here:
        <button
          @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
        >
          ⨯
        </button>
      </div>
    </demo-overlay-system>
  `;
};

Nested Overlays

Overlays can be nested, as the demo below shows. It's also possible to compose a nested construction by moving around dom nodes.

export const nestedOverlays = () => {
  return html`
    <demo-overlay-system .config="${withModalDialogConfig()}">
      <div slot="content" id="mainContent" class="demo-overlay">
        open nested overlay:
        <demo-overlay-system .config="${withModalDialogConfig()}">
          <div slot="content" id="nestedContent" class="demo-overlay">
            Nested content
            <button
              @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
            >
              ⨯
            </button>
          </div>
          <button slot="invoker" id="nestedInvoker">nested invoker button</button>
        </demo-overlay-system>
        <button
          @click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
        >
          ⨯
        </button>
      </div>
      <button slot="invoker" id="mainInvoker">invoker button</button>
    </demo-overlay-system>
  `;
};

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